Method for Gradually Adjusting Screen Brightness When Switching Operating System

1. A method for adjusting screen brightness when switching an operating system, used for adjusting a brightness value of a screen of an electronic device when the electronic device is switched from a first operating system to a second operating system, the method comprising: receiving an operating system switching signal; obtaining a first brightness value of the first operating system; adjusting the screen brightness from the first brightness value to a predetermined second brightness value; switching the first operating system to the second operating system; and adjusting the screen brightness from the second brightness value back to the first brightness value, wherein obtaining the first brightness value comprises: determining whether the first operating system operates in a working mode; in response to determining that the first operating system is operated in the working mode, sending a brightness value request message to the first operating system for acquiring the first brightness value utilized by the first operating system when the first operating system operates in the working mode; and in response to determining that the first operating system is not operated in the working mode, reading the first brightness value of the first operating system from a memory of the electronic device.

2. The method for adjusting screen brightness when switching an operating system according to claim 1 , further comprising: transmitting the received first brightness value to the second operating system.

3. The method for adjusting screen brightness when switching an operating system according to claim 1 , wherein the step of receiving the operating system switching signal comprises: determining whether a switching key of the electronic device is triggered; when the switching key is triggered, generating the operating system switching signal; and receiving the operating system switching signal generated by the switching key.

4. The method for adjusting screen brightness when switching an operating system according to claim 3 , wherein the switching key is a physical key disposed on the electronic device or a virtual key displayed on the screen of the electronic device.

5. The method for adjusting screen brightness when switching an operating system according to claim 1 , wherein the step of obtaining the first brightness value of the first operating system comprises: receiving the first brightness value sent back by the first operating system according to the brightness value request message.

6. The method for adjusting screen brightness when switching an operating system according to claim 5 , wherein the controller comprises an embedded controller (EC).

7. The method for adjusting screen brightness when switching an operating system according to claim 5 , wherein the first brightness value of the first operating system recorded in the memory is stored at a set time when the first operating system operates in the working mode or before the first operating system leaves the working mode.

8. The method for adjusting screen brightness when switching an operating system according to claim 1 , wherein the first brightness value of the first operating system is obtained by a controller of the electronic device, the step of obtaining the first brightness value of the first operating system comprises: directly reading the first brightness value of the first operating system from a memory built in the controller.

9. The method for adjusting screen brightness when switching an operating system according to claim 8 , wherein the controller comprises an embedded controller (EC).

10. The method for adjusting screen brightness when switching an operating system according to claim 1 , after adjusting from the first brightness value to the second brightness value, further comprising: maintaining the screen brightness at the second brightness value for a predetermined period of time; adjusting the screen brightness from the second brightness value back to the first brightness value after the predetermined period of time.

11. The method for adjusting screen brightness when switching an operating system according to claim 1 , wherein the step of adjusting the screen brightness from the second brightness value back to the first brightness value further comprises: detecting a current ambient brightness value; adjusting the first brightness value according to the ambient brightness value to obtain an adjusted first brightness value which is a function of both the first brightness value of the first operating system and the current ambient brightness value; and adjusting the screen brightness from the second brightness value to the adjusted first brightness value.

12. The method for adjusting screen brightness when switching an operating system according to claim 11 , wherein the step of adjusting the first brightness value according to the ambient brightness value comprises: determining whether the ambient brightness value is greater than or equal to a predetermined brightness value; if the ambient brightness value is greater than or equal to the predetermined brightness value, upwardly adjusting the first brightness value by a first ratio to obtain the adjusted first brightness value; and if the ambient brightness value is smaller than the predetermined brightness value, downwardly adjusting the first brightness value by a second ratio to obtain the adjusted first brightness value.

13. The method for adjusting screen brightness when switching an operating system according to claim 1 , wherein the second brightness value comprises a full-black value.

14. The method for adjusting screen brightness when switching an operating system according to claim 1 , wherein the steps of adjusting the screen brightness from the first brightness value to a predetermined second brightness value and adjusting the screen brightness from the second brightness value back to the first brightness value are performed according to a curve function.

15. The method for adjusting screen brightness when switching an operating system according to claim 1 , wherein the step of adjusting the screen brightness of the electronic device is performed by a pulse width modulation (PWM) module.

16. The method for adjusting screen brightness when switching an operating system according to claim 1 , wherein the electronic device is a notebook, an ultra mobile PC (UMPC), or a personal digital assistant (PDA).

17. An electronic device, comprising: a first operating system; a second operating system; a screen; and a controller, comprising a memory for storing a first brightness value of the first operating system, the controller is configured for determining whether the first operating system operates in a working mode, wherein in response to determining that the first operating system is operated in the working mode, the controller sends a brightness value request message to the first operating system for acquiring the first brightness value utilized by the first operating system operates in the working mode, in response to determining that the first operating system is not operated in the working mode, the first brightness value of the first operating system is read from the memory of the controller, the controller is used for adjusting the screen brightness from the first brightness value to a predetermined second brightness value, and adjusting the screen brightness from the second brightness value back to the first brightness value after the first operating system is switched to the second operating system.

18. The electronic device according to claim 17 , wherein the device comprises a switching key for generating an operating system switching signal, and the switching key is a physical key disposed on the electronic device or a virtual key displayed on the screen of the electronic device.

19. The electronic device according to claim 17 , wherein the controller comprises an EC.

20. The electronic device according to claim 17 , wherein the electronic device is a notebook, a UMPC, or a PDA.

21. The electronic device according to claim 17 , wherein the controller further comprises a PWM module for gradually adjusting a brightness value of the screen of the electronic device.